Water rheostat control



Dec. 28, 1948. v, c pw c 2,457,124

WATER RHEOSTAT CONTROL Filed July 9, 1945 INVENTORS VINCENT CHADWRCK OLAF LE. HALLBERG I QW W ATTORNEY Patented Dec. 28, 1948 UNITED WATER RHEOSTAT CONTROL Vincent Chadwick, Chelsea, and Olaf I. E. Hallberg, Boston, Mass.

Application July 9, 1945, Serial No. 604,006

(Granted under the act of March 3, 1883, as

7 Claims.

amended April 30, 1928; 370 O. G.

This invention relates to a device for controlling water rheostats such as are used in testing generators and the like.

It is a common practice to test generators by connecting their output leads to a water rheostat and varying the electrical load for the test by moving the electrodes of the rheostat either to ward or away from each other, moving the electrodes further into or out of the saline solution, or by increasing or decreasing the salinity of the solution. The above practices are used either singly or in combination and have the disadvantages of being cumbersome, awkward, and generally unsatisfactory, particularly in performing tests where a fine degree of control is required.

It is accordingly an object of the present invention to provide a device for controlling a water rheostat that is simple in construction and that permits the test load on the particular electrical apparatus being tested to be readily changed from maximum to minimum or any intermediate amount, easily, without disturbance to the conventional elements of the rheostat or the concentration of its solution.

It is another object of the invention to provide a device of this character, the mode of operation of which lends itself to the securing of an extremely fine degree of control in varying the load applied to the particular electrical apparatus being tested.

With the above and other objects and features in view, the invention will now be described with reference to the accompanying drawings which illustrate a preferred embodiment of the invention and will be pointed out in the claims.

In the drawings:

Fig. 1 is a side elevation of a water rheostat partly in section andshowing the improved control device applied thereto, a generator and its connection to the rheostat being shown diagrammatically;

Fig. 2 is an end elevation of the rheostat; and,

Fig. 3 is a detailed plan view of the friction members for holding the insulating curtain of the device in its adjusted position.

The water rheostat is comprised of a tank Ill containing a saline solution 12. The conventional electrodes l4 are supported in spaced relation to each other adjacent to the opposite ends of the tank as by brackets IS. The electrodes are substantially immersed in the solution I2 and are provided at their upper ends with electrical terminals for connection to the particular electrical apparatus to be tested. Herein, the rheostat is shown as connected between the output leads of 2 an electric generator diagrammatically indicated at Hi.

The improved control device comprises a shaft or rod 20 extending transversely of the center of the tank I0 and rotatably mounted at its opposite ends in bearings 22 secured on the upper edges of the sidewalls of the tank. The shaft is arranged to be rotated by a handwheel 24 fixed on one end of the shaft that projects beyond one of the bearings 22. A sheet or curtain 26 of rubber or other insulating material of a width corres ponding substantially to the interior width of the tank I!) is secured at one end to the rod 20. The free end of the curtain 26 i provided with a hem 28 in which is inserted a rod 30 for the purpose of weighting this end and causing the curtain to lower into the solution as the handwheel 24 is rotated to unreel the curtain from the shaft. Flanges or disks 32 are secured to the shaft 20 adjacent to the edges of the curtain to act as guides for insuring even and regular winding and unwinding thereof as the shaft is rotated in one direction or the other. Any suitable friction means may be provided for holding the rod 20 and curtain 26 in adjusted position. The means illustrated in Fig. 3 for this purpose includes two members 34 and 36. The member 34 is secured by screws 38 to one sidewall of the tank l0 and has its forward end lying in contact with a portion of the outer face of disk 32. The member 36 is pivotally spaced from the member 34 by a lug 40 at one end and has its opposite end held in frictional contact with a portion of the inner face of disk 32 by a screw 42 passing through the member 36 and threaded into the member 34. The screw 42 is set up so that just suflicient frictional pressure is applied to the disk 32 to hold the shaft 20 and curtain 26 in adjusted position and still permit of ready rotation of the shaft for further adjustment of the curtain by the handwheel 24.

In operation, the output leads of the generator iii are connected as illustrated in Fig. 1 to the terminals of the electrodes I4. With the generator running, the desired variable test loads thereupon are obtained by raising or lowering the curtain 26, the curtain acting as an electrical barrier between the electrodes, and the unrestricted area of flow of current through the solution being governed by the extent of depth to which the curtain is lowered. When the curtain 26 is fully wound upon the rod 20, the maximum load is placed upon the generator or other apparatus being tested. Conversely, when the curtain is fully lowered so that its free end rests upon the bottom of the tank ID the minimum load is placed upon the generator.

It has been found in practice that a much finer degree of control is obtained by the use of this device than has been heretofore obtained by the old practice of moving the electrodes or changing the concentration of the solution.

The invention described herein may be manta factured and used by or for the Government of the United States of America for Government purposes Without the payment of any royalty thereon or therefor.

Having described the invention what is claimed as novel and desired to be protected by Letters Patent of the United States is:

1. A device for controlling a rheostat including a tank containing electricity conducting liquid and electrodes mounted in spaced relation therein, said device comprising a rotatable shaft mounted transversely of said electrodes, a curtain of insulative material wound upon said shaft, means for weighting the free end of said curtain, and a member on said shaft for rotating the latter to raise or lower the curtain between said electrodes.

2, A device for controlling a rheostat including a tank containing electricity conducting liquid and electrodes mounted in spaced relation there-- in, said device comprising a rotatable rod mounted transversely above the space between said electrodes, a curtain of insulating material adapted to roll upon said rod, means for rotating the rod to raise or lower said curtain between electrodes, and friction means for retaining said curtain in adjusted position.

3. A device for controlling a fluid rheostat having spaced electrodes comprising a roll of insulating material, said roll being adapted to unroll to provide an adjustable sheet of insulating material in the path of current flow between said electrodes.

4. A device for controlling a rheostat including electrodes immersed in spaced relation in a tank of electricity conducting liquid, said device comprising a roll of insulating material, said r011 being adapted to unroll to provide a sheet of insulating material forming an electrical barrier in the path of current flow between said electrodes, and means for rotating said roll to govern the path of current flow between said electrodes.

5. A device for controlling a rheostat includin electrodes immersed in spaced relation in a tank of electricity conducting liquid, said device comprising a roll of insulating material, said roll being adapted to unroll and provide a sheet of said insulating material forming an electrical barrier in the path of current flow between said electrodes, and means for rotating said roll for variably positioning said sheet between said electrodes, said sheet being adapted to govern the unrestricted area of current flow through said liquid between said electrodes from a predetermined maximum value to substantially zero.

6. A rheostat including a tank containing conducting fluid, electrodes supported in said tank in spaced relation and being immersed in said fluid, a flexible and end weighted insulating curtain adapted to be lowered into said fluid to provide an electrical barrier in the path of current flow between said electrodes, the extent of depth to which said curtain is lowered into said fluid determining the unrestricted area of flow of current through said fluid between said electrodes, said insulating curtain being arranged whereby said area is substantially uniformly variable throughout the adjustment of curtain depth from a predetermined maximum value to substantially zero.

I. A rheostat comprising, a tank containing electricity conducting fluid, electrodes supported in said tank in spaced relation and being immersed in said fluid, said tank and said fluid having a substantially rectangular cross section in the region between said electrodes, a rotatable rod mounted transversely of said tank above the fluid between said electrodes, a substantially rectangular curtain of insulating material attached at one end. thereof to said rotatable rod, the width of said insulating curtain being substantially equal to the width of said tank in said region between electrodes, the end of said curtain opposite the end attached to said rod being freely suspended into said tank and said fluid, means for rotating said rod for governing the extent of depth to which said freely suspended end of said curtain is lowered into said fluid, whereby rotation of said rod determines the unrestricted area of current flow through said fluid between said electrodes.

VINCENT CHADWICK. OLAF I. E. HALLBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 374,404 Field Dec. 6, 1887 1,023,602 Wallman Apr. 16, 1912 1,550,164 Heinrich July 9, 1945 

